Here is the scoop. I have a Rem 700 in 338Win. The gun is factory with the exception of a Bansner High Tech stock. The gun was always a so so shooter. By that I mean it would soemtimes shoot groups an inch or less, but generally it averaged 1 1/2 inches overall.

A few years back I fire lapped the gun using the Tubbs Final Finish system hoping to improve accuracy. The gun cleans much better, but accuracy didn't improve. Over the next few years accuracy has deteriorated to where groups are 2 to 3 inches.

Now for the question. Is it worth to try and re-chamber the existing barrel or is a new barrel the better option? I can live with 1 1/2 inch accuracy if I can get it again. I'm thinking the throat may be worn from the fire lapping and if the gun could be re-chambered it might come back to where it was before. This would cost less than a new barrel and make me happy enought with this gun. Thoughts?

Another question. If I was to re-chamber to a 338 RUM, are there any modifications required to the action?

Thanks
Jeff

If that was my gun, I'd scrub the barrel with ammonia until it was totally clean of copper and then glass bed the barreled action full length and then float the barrel.

Reload some ballistic tips, some Interlocks and some A-Frames or North Forks. If none of them shot reasonable groups, I'd trade the rifle. No rechambering, no rebarreling.....trade the thing.

This is assuming the scope is a proven scope with a history of performance.

Well, I think that you're right. The Final Finish system smoothed out your barrel but washed out the throat.

If you pull the barrel and cut a couple of threads off and put it back on, it should help you get the throat back. I'll bet that it will free float the barrel at the same time because the taper of the barrel will move back and give you a lot of room in the barrel channel.

quote:

Over the next few years accuracy has deteriorated to where groups are 2 to 3 inches.

How many rounds did you shoot during this deteriation process? If its less than 1000 I doubt your chamber is at fault.

I would clean your rifle, and I don't mean a patch or two, get serious and clean it until all the copper comes out. use something like shooters choice copper remover, and scrub and clean it hard.

Next question, do you handlaoad? If you do check your case lengths on your brass, if its long trim it. This is a very common problem and .0030 long will put your accuracy in the toilet.

Last question, when you were fiddling with this rifle did you ever check the screws in the floorplate for torque? Remingtons need to be torqued with inch pound torgue wrench for best accuracy. I don't remember off the top off my head but its somewhere around 40-60 inch pounds.
Another question did you ever check the lug engagement on your bolt? Best accuracy requires full contact, and most factory guns have 70-85% contact, they simply don't spend the time to do it right on production rifles.

Another item to look at is the crown. Is it a stock factory? If so eyeball it closely and make sure it has no nicks or damage thats a sure way to have your groups go south. I use a target crown on all my custom rifles, they don't damage as easy in the field.

If your worried about the bore look after its all clean look down it with a bore light and eyeball for erosion right by the throat, if is bad you should see erosion for 3/4-1 1/2" down the barrel from the chamber. If this is the present forget about rechambering, it won't fix it.

If you don't get that barrel shooting better I wouldn't bother with rechambering it. But I honestly think if you check the above it should be back to where it was, if you lap your lugs maybe even better.

Sounds to me like you are looking for a reason to go to the ultra mag. If that is so get a new barrel. It will be like having a new gun that will probably shoot better.

It is not an easy task to go from a standard 338 to a 338 RUM.

quote:

Originally posted by JAB:
Here is the scoop. I have a Rem 700 in 338Win. The gun is factory with the exception of a Bansner High Tech stock. The gun was always a so so shooter. By that I mean it would soemtimes shoot groups an inch or less, but generally it averaged 1 1/2 inches overall.

If it was mine, I'd just re-barrel. You have a fine rifle, but the Barrel Lapping does tend to wear out a barrel.

quote:

If I was to re-chamber to a 338 RUM, are there any modifications required to the action?...

Just save up and buy a new one.

If you send the first M700 to someone like Pac-Nor, they can do a rebarrel rather inexpensively and you will probably have better accuracy than you originally experienced. Be sure to compare prices with having it done locally, because you may have an excellent GunSmith close by.

I've seen a good many 300RUMs and 338RUMs at the Range and they all shot great. The Muzzle Brake that comes with them works amazingly well, but as usual, they sure are loud. If you plan to hunt with Ear Plugs, it should do just fine though.

IF you are talking about rechambering a barrel that shoots poorly due to a deteriorated bore, rechambering the thing won't help! If the bore is worn out, you need a new barrel, or to rebore the present one to a larger caliber, like .358, 9.3mm, or .375.